(1) Field of the Invention
The present invention relates to a circuit board inspection apparatus and particularly to an automatic inspection apparatus for handset circuit boards.
(2) Description of the Prior Art
Automatic optic inspection (AOI) has been successfully applied on the production lines of printed circuit board (PCB) after nearly ten years of research and development. With the circuit elements increasingly miniaturized and condensed, surface mount technology (SMT) factories in the PCB manufacturing industry have to adopt AOI apparatus on the production lines. This is because the small and condensed electronic elements on the circuit board can no longer be identified by operator's eyes on the production lines. AOI system provides a reliable and consistent inspection, and keeps accurate inspection records. In addition, the AOI system can execute the inspection repeatedly and accurately. The inspection scope includes whether the elements have void soldering, short circuit, deformation or shortage, and whether the elements are soldered properly without deviation or uneven solder paste distribution. Finally computers are used to store, analyze and process the inspection results.
The handset main board fabrication process also needs the help of AOI system. As the size of the handset shrinks continuously, the main board also shrinks. To rely on human eye to inspect whether the elements are precisely and properly soldered on the main board is very difficult and inefficient. Hence the AOI system becomes the only and most efficient equipment. However, there are still problems when using the AOI system to inspect the handset main boards as indicated below.
Refer to FIG. 1 for a handset main board (abbreviated panel 10 hereinafter) which generally contains four identical sub-panels 12 (ranging from 4 to 12 sub-panels). Each sub-panel 12 has many surface mount devices(SMD) (not shown in the drawing) soldered on the upper and lower surfaces thereof. The panel 10 has to go through an inspection process to check whether the devices are accurately soldered on each sub-panel 12.
Refer to FIG. 2 for a conventional panel inspection process. First, inspection of the upper surface of a panel is executed. The process includes: bonding a barcode 14 on the upper surface of the panel 10(step 101); next, performing inspection through an AOI system (step 102); the AOI system determining whether defects are found on the soldered elements of the sub-panel 12(step 103) and at the same time reading the barcode 14 of the panel 10; performing manual inspection if the AOI system determines any soldered element on any sub-panel 12 is defective (step 104); confirming again abnormal conditions of the soldered elements on the sub-panel 12(step 105); proceeding panel repair process if the inspection result proves the defect existed and generating repair records (step 106); continuing inspection of the lower surface of the panel 10 if no defect is found in the upper surface inspection.
At step 103, if it is determined that there is no defect on the soldered elements of the sub-panel 12, directly proceed the inspection of the lower surface of the panel 10 (step 107 to step 113). The processes are same as those previously discussed, details are omitted. The barcode 14 of the panel 10 mainly aims to identify the panel 10 and link to the inspection and repair records of the panel 10 for the follow on process and analysis. However, in the later stage processes, after the panel 10 and the sub-panel 12 are separated, the individual sub-panel cannot be identified with its original panel. As a result, the corresponding inspection records are useless. In view of this problem, the present invention aims to provide a circuit board inspection apparatus that can link the inspection records of the panel to the corresponding sub-panel after they are separated.